Remove USE_METADATA.

It has been on by default for quite some time now.

ir/irclass.cpp

@@ -88,7 +88,6 @@ LLGlobalVariable * IrStruct::getClassInfoSymbol()
     classInfo = new llvm::GlobalVariable(
         *gIR->module, tc->getMemoryLLType(), false, _linkage, NULL, initname);
 
-#if USE_METADATA
     // Generate some metadata on this ClassInfo if it's for a class.
     ClassDeclaration* classdecl = aggrdecl->isClassDeclaration();
     if (classdecl && !aggrdecl->isInterfaceDeclaration()) {
@@ -109,7 +108,6 @@ LLGlobalVariable * IrStruct::getClassInfoSymbol()
         node->addOperand(llvm::MDNode::get(gIR->context(),
             llvm::makeArrayRef(mdVals, CD_NumFields)));
     }
-#endif // USE_METADATA
 
     return classInfo;
 }